Thrikarthika, or Trikartika, is the festival of lights celebrated in Kerala on the Kartika Nakshatram (star) in the Malayalam month of Vrischikam (November – December). It usually falls on the full moon day in the month and on the day all the houses, streets and temples are well lit with traditional oil lamps. The festival is mainly observed in South Kerala. In 2015, the date of Thrikarthika is November 25.

Thrikarthika festival is not dedicated to any particular God or Goddess in Hindu pantheon. But some people do claim that is dedicated to Shakti – popularly known as Bhagavati in Kerala. Some people claim it is an ancient form of nature worship.

On the Thrikarthika day after sunset, houses, streets and temples are decorated with special oil lamps. Earlier people used to make use of the shell of Marotika to light lamps. Now the Marottika shell is widely replaced by clay diya (known as idinjil or chirathu) and candles.

The stems of banana (plantain) and tender leaves of coconut tree are used to decorate the Thrikarthika lamps. The lamps are placed on the banana stems supported by coconut leaves.

People who have domesticated animals also decorate the cowshed and other places used by animals. Special food is prepared using Tapioca, elephant yam and other tubers with lot of grated coconut on the day and is known as Kartika Puzhukku.

The full moon night and the Thrikarthika lamps complement each other giving an awe inspiring feeling to the viewers.